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Poster: adelmand Date: Aug 3, 2003 6:08am
Forum: prelinger Subject: vertical lines in converted video?

I've converted several films fairly successfully to DV from mpeg2 using the quicktime mpeg2 decoder, but I always get vertical lines in the converted files. The visibility of these lines varies depending on the contrast between various areas of the picture - here's an example:
Does anyone know what the cause of this might be, or how to remedy it? I've also experienced this problem with DivA, but I think that might also be using the QT codec.



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Poster: Ryan Schweitzer Date: Aug 7, 2003 8:31pm
Forum: prelinger Subject: Re: vertical lines in converted video?

Yep, it looks like the QT codec is simply interpolating the horizontal resolution, since most of the MPEG-2 files on this site are encoded at either 360x480 or 480x480, instead of the standard 720x480 resolution (also referred to as ITU-601 or D1 resolution) that full-resolution MPEG-2 video, and DV video as well, use.

The QT codec is simply interpolating the horizontal pixels, whether it be 360 or 480 of them, to fit in a 720 horizontal pixel resolution. I'm assuming it must repeat every other pixel or something similar.

My RealMagic Hollywood+ card in my PC that I use for viewing Prelinger's (and others) MPEG-2s on my TV set does this exact same interpolating with the horiz. resolution, slightly noticeable vertical lines that look exactly the same as the example framegrab you've posted a link to.

I dunno if there's a way around this, since the codec is trying to scale the res. of the MPEG-2 files up to standard MPEG-2/DV resoultion, by way of pixel interpolation...


This post was modified by Ryan Schweitzer on 2003-08-08 03:31:21